Answer:
95.64% probability that pledges are received within 40 days
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:

What is the probability that pledges are received within 40 days
This is the pvalue of Z when X = 40. So



has a pvalue of 0.9564
95.64% probability that pledges are received within 40 days
If they are next to each other, they multiply.
Answer:
15.5833333333
Step-by-step explanation:
12 1/4 + 3 1/3 = 15.5833333333
Hope this helps :)
Answer:
1.3%
Step-by-step explanation:
Phat = 0.53
1 - phat = 1 - 0.53 = 0.47
Sample size, n = 5913
Assume the confidence level = 95%
Zcritical at 95% = 1.96
Margin of Error = Zcritical * √(phat(1 -phat)) / n
Margin of error :
1.96 * √((0.53 * 0.47) / 5913)
1.96 * 0.0064905
= 0.0127215
= 0.0127215 * 100%
= 1.272%
= 1.3%